Blood Transfusion After Myocardial Infarction: Friend, Foe or Double-Edged Sword?

Combined mechanical and pharmacological interventions constitute the cornerstone of therapy for patients with ST-segment elevation acute myocardial infarction (AMI). These increasingly complex interventions offer morbidity and mortality advantage but are associated frequently with bleeding complications. Major bleeding is probably the most important non-cardiac complication in patients undergoing coronary artery intervention. Prior studies have identified anemia as a strong independent predictor of mortality and adverse cardiac events in this patient population. Limited data are available to guide transfusion decisions in patients with coronary artery disease and anemia either at baseline or after a complication of an angioplasty procedure.The CADILLAC study sought to determine the relationship between red blood cell transfusion and clinical outcomes in patients undergoing primary percutaneous coronary intervention for AMI. Out of 2,060 randomized patients, 82 (3.98%) received red blood cell transfusion during index hospitalization. Transfusion was independently associated with baseline anemia, older age, multivessel disease, and female gender. Patients transfused, versus patients not transfused, had significantly higher rates of one year mortality (23.9% vs. 3.4%), disabling stoke (2.5% vs. 0.5%), reinfarction (7.0% vs. 2.2%) and composite major adverse cardiac events (41.0% vs.16.6%). After multivariable adjustment for potential confounders, red blood cell transfusion was independently associated with mortality at 30 days and one year (hazard ratio 4.71 and 3.16 respectively, both p=0.0005). The authors concluded that red blood cell transfusion after primary angioplasty in the setting of an AMI may be harmful or alternatively transfusion could be a marker of markedly increased risk, with further randomized studies needed to determine the optimal threshold for red blood cell transfusion in this patient population setting